msm: kgsl: Cleanup the IFPC powerup lists

Cleanup the code that manages the IFPC powerup lists in anticipation of
adding more target specific lists. This consolidates the code and
simplifies the effort to add new items to the list.

Change-Id: Ic0dedbad2cd0da48e7899ecc7ea019d2b175e32f
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>